Surveying, Mapping and GIS

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    Exploring all aspects of mapping and geography, from field data collection, to mapping and analysis, to integration, applications development, enterprise architecture and policy
Showing posts with label geodesy. Show all posts
Showing posts with label geodesy. Show all posts

A Composition on Surveying and Geodesy

Posted by Dave Smith On 2/10/2008 10:23:00 AM 1 comments

Poetic Verse on Surveying and Geodesy...

Survey the Whole, nor seek slight faults to find,
When Nature moves, and Rapture warms the Mind.
SCIENCE! thou Daughter of the Skies, 'tis thine
To make Perfection in her Beauties shine;
Thy darkest Clues endear the anxious Mind,
When Study labours thy great Worth to find:
In thy rich Stores our lab'ring Thoughts absorb,
Measure the Earth, and each celestial Orb.
Behold yon Gardens, Trees, and shady Bow'rs,
So often chequer'd with delightful Flow'rs;
Behold yon Buildings, high ascending Spires,
Yon Water, Castle, Mountains, stately Tow'rs,
Yon curing Brook, and cool expanding Shade,
Whose winding Course surrounds the fragrant Mead;
All their Dimensions we with Ease impart,
By GEODASIA, and the Rules of Art.


Thomas Sadler, 1771

The above is excerted from "To Arthur Burns, on his New Treatise, entitled, GEODASIA IMPROVED: A Poem", written by Thomas Sadler, Whitechurch, 1771.

Some background on Sadler from SurveyHistory.org, the Virtual Museum of Surveying:
Mr. Sadler was a devoted student of Burns', a leading surveyor of the day.

The poetic style, like much of the language of the time, was ornate. The Century Dictionary of 1889 describes "Geodasia": Formerly, the art of land surveying in general, but now restricted to that branch of applied mathematics, distinctively called Higher Geodesy which investigates the figures and areas of large portions of geographical positions and the azimuths of directions, the general figure of the earth, and the variations of gravity in different regions, by means of direct observation and measurement."

Pennsylvania Surveyor's Conference 2008

Posted by Dave Smith On 1/20/2008 09:36:00 AM 0 comments

I am looking forward to going to the Pennsylvania Society of Land Surveyors' 2008 Conference. It kicks off tomorrow in Hershey, PA... There I will catch up with some of my old surveying colleagues and friends, as well as ping them on many of the other things that I've been dealing with, such as work on updating the NCEES Model Law via their Uniform Procedures and Legislative Guidelines Committee (UPLG) and Continuing Professional Competency for Land Surveyors as recently introduced via legislation in Pennsylvania - and potentially subject to an updated legislative effort, as well as many of the other things I work toward, such as data standards and geodesy, and many other plates spinning and hats I wear.
I am presently wrapping up a weekend spent with the UPLG Committee in Florida - which again raises some of the questions of defining practice, as regulated by law - with particular, sensitive crossover issues in Surveying being GIS and Photogrammetry, but also Engineering and other fields.

IT Generalists

Posted by Dave Smith On 6/10/2007 10:57:00 PM 1 comments

After combating on proposals for a few recent projects, I am getting a bit frustrated with the preponderance of IT generalist firms chasing after the same work we do. Seems there is still a notion out there that information technology is the solution to everything. Problem is, the reality is that IT in and of itself is not and will be a driver to compare with the actual business. And if the actual business requires understanding of geospatial analysis, or of geodesy and high-accuracy locational data, or of environmental science, or of transportation and congestion, then these are still the primary drivers.

Sure, you can hire some button pushers cheap... but will they really serve the need? Maybe, but most likely not. Will they display any thought leadership or vision? Definitely not. Is any of it meaningful to the IT generalists? No. Just butts in seats, generating revenue, quantity versus quality. Whatever happened to qualifications, domain expertise and past performance?

South Carolina GIS Surveyor

Posted by Dave Smith On 5/09/2007 08:09:00 PM 2 comments

I haven't posted in a while, have been busy with a number of things, such as new projects kicking off, proposals to write, along with a number of meetings.

This weekend, I got home from a couple of meetings, the NCEES Northeast Zone meeting and Colonial States Boards of Surveying Registration. One of the interesting things I learned a bit more about there was the South Carolina system of tiered land surveying licensure. One that struck me as odd is the GIS Surveyor licensure that was passed several years ago.

In South Carolina, they have implemented a series of surveying licenses, which are subsetted to certain disciplines - photogrammetry and geodetic surveyor were two of the ones I had heard discussed more about. With these, it's historically been my understanding and feeling that geodesists and photogrammetrists pretty much stuck to their respective fields, with little overlap or interest in boundary work or other aspects of surveying. GIS Surveyor seems like an odd one, though.

This is how South Carolina has implemented it:

Historically, geodesy and photogrammetry have gone hand-in-hand with surveying, each a very specialized subdomain. Historically, however, neither of these have required licensure in most areas, and given the limited numbers of practitioners in these fields, and the limited number of litigations or other legal conundrums generally associated with geodesy or photogrammetry, I am not entirely certain that licensure even is warranted.

However, GIS is such a broad field. GIS supports so many disciplines, such as archaeology, urban and regional planning, resource conservation, geology, socioeconomics, and so on. In terms of overlap with surveying, it would be a Venn diagram showing a modest overlap - particularly where it comes to cadastral data, geodesy, photogrammetry, and locational data acquisition and locational data quality. But there is plenty to GIS which has nothing whatsoever to do with surveying.

The question of licensure brings up a number of other questions. Has the practice of GIS been trouble-free? Not at all. Has GIS been misused, have lawsuits arisen due to improper use of GIS? Yes. And unfortunately many of these have been as a result of improper use of cadastral data, where for instance tax-map grade GIS data was used to pursue building setback violations, or other ordinance-based conundrums, rather than relying on an actual field survey to verify lines of possession and improvements in the field. In some instances, unlicensed GIS practitioners have done such things as utilized handheld GPS units to locate property corners and similar features in the field. When it comes to these sorts of things, does GIS trespass on practice of land surveying? In most states, yes. And as such, they can be pursued under existing land surveying licensure laws.

In some instances, GIS data must be strictly controlled, due to legal implications, due to pending litigation or cost recovery in the instance of environmental cleanup data, due to loss of sensitive and endangered species in the case of conservation, or risk of looting in the case of archaeological data, and so on. In some of these instances, perhaps professional licensure may indeed be appropriate for GIS practitioners - the "protect the public" part of the equation being bolstered with risk to practitioners who do not exercise proper care, such as fines or loss of licensure. But does that have anything to do with surveying? No. Another approach is through self-policing within the GIS community, as some current proposals have it, but even good intentions pave the road to hell.

It will be interesting to see what the times bear.

For additional background, I have found a number of discussions on this - yet they all just seem to scratch the surface...

Information posted to the South Carolina State Mapping Advisory Committee

Further correspondence posted by Patrick J. Bresnahan, Richland County SC

NGS 10-Year Plan: Call for Comments

Posted by Dave Smith On 2/23/2007 07:17:00 PM 0 comments

The National Geodetic Survey, in keeping with quite a few innovations and revelations to coincide with their 100th anniversary, has unveiled a copy of their 10-year plan, and are soliciting comment:

During the last year, NGS has spent considerable effort refining its mission, vision and strategy for the future. The result of this effort is the NGS 10 year plan. Because any plans for the future will affect the NGS stakeholders and the general public, NGS is releasing this plan in draft form for a public comment period lasting until March 31, 2007. NGS is interested in hearing all feedback on the proposed plan over the next few weeks. NGS will also discuss and take comments on the 10 year plan at the ACSM conference in St. Louis. This will take place during the first half (8:30 a.m. - Noon) of the "National Geodetic Survey and Partners" meeting on Sunday, March 11.

Please note that this document is in draft form. At this time NGS is seeking comments on the content of the plan. Once those comments have been received and incorporated into the plan the document will undergo a professional editorial review to address administrative (spelling, punctuation, etc.)
issues. Following the public comment period, NGS will consolidate all feedback and issue a final copy of the 10 year plan some time in April 2007.

Click here to download the draft of the NGS 10 year plan.
Click here to go to the comment template for providing feedback on the plan.Comments will be mailed to the NGS 10 year plan working group.



I am currently reviewing the document, it's around 42 pages. Some interesting touchpoints within the document:

"...the geodetic latitude, longitude and height of points used in defining the NSRS should have an absolute accuracy of 1 millimeter at any time."

"...the gravimetric geoid used in defining the NSRS should have an absolute accuracy less than 1 centimeter anyplace at any time."

"NGS will publish all coordinates of defining points of the NSRS with an epoch tag and will furthermore publish velocities relative to that epoch-tagged set of coordinates."

"NGS will therefore publish all coordinates and velocities of NSRS defining points in both the most recent official U.S. Datums and the most recent realization of the International Terrestrial Reference Frame (ITRF). Furthermore, NGS will provide simple transformation tools between all historic and current datums and reference frames used by NGS, in 4 dimensions if possible."

and...

"NGS will validate local capacity for accurate positioning through direct interaction with a county geospatial representative and evaluation of that county’s access to the NSRS."

Thanks to John Halleck for pointing some of these out, to pique everyone's interest. Some very lofty goals indeed...

I just came across a spanish-language blog, called TopoNorte - the author features a wide variety of great geospatial and surveying content. Some items I thought were particularly great:
Cadastral mapping of Spain, using Google Maps: http://www.goolzoom.com/


And here, a publication on geodesy and UTM grids by Professor Ignacio Alonso Fernández-Coppel at the University of Valladolid:

http://www.elagrimensor.com.ar/elearning/lecturas/Las%20coordenadas%20geograficas.pdf

Posted by Dave Smith On 2/12/2007 10:25:00 PM 0 comments

Thanks to Gene Kooper for this great illustration of a theodolite from J. Johnson's 1886 text, "Theory and Practice of Surveying".




NAD83 (NSRS2007) is now online!

Posted by Dave Smith On 2/09/2007 06:01:00 PM 0 comments


Exciting news: In keeping with their aims for big ways to commemorate their 200th anniversary, the National Geodetic Survey has just put the new National Readjustment of NAD83 online.


Some PowerPoint presentations on the adjustment are provided here:
Data is downloadable in "Re-Adjustment Data Format" here: http://www.ngs.noaa.gov/NationalReadjustment/rdf.html

Many thanks to NGS and all the good people who put a lot of time and effort into this - it will be great to have all of these stations tied to a consistent, seamless adjustment instead of many independent regional adjustments, as well as having NAD83 tied to CORS for concurrence.

NGS 200th Anniversary and NAD83(NSRS 2007)

Posted by Dave Smith On 1/28/2007 07:07:00 PM 0 comments


The 200th Anniversary of the National Geodetic Survey is coming up - from origins as the Survey of the Coast, signed into existence by Thomas Jefferson, on February 10th, 1807 to the present, a legacy of much excellent work. NOAA and NGS have many events planned in celebration of their 200-year legacy of success.

With this, also comes the unveiling of the National Readjustment of NAD83 - NAD83(NSRS 2007). A key benefit of this will be in that this adjustment will be performed using all data in the National Spatial Reference System (NSRS), as opposed to the previous efforts, which were statewide and regional. The first, NAD83(1986) was performed on states, multi-state regions and so on.
Later on, with improved GPS capability came NAD83(HARN), referencing the High-Accuracy Reference Network. This exposed positional issues in the previous NAD83(1986) adjustment, and again, the HARN adjustments were performed on a state or regional basis.

As time progressed, we saw the emergence of the national Continuously-Operating Reference Stations (CORS) system - and with this, we gained a national network of GPS coordinates, which however exposed inconsistencies with the state and regional networks.
Now, with NAD83(NSRS 2007), 70,000 GPS points nationwide have been put into the mix, in a massive effort to place all of these on a common reference system, to eliminate the longstanding inconsistencies from adjustment to adjustment, network to network. With the excellent leadership of people at NGS like Dave Doyle, this release will be a boon to survey-grade, geodetic projects nationwide.


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Pennsylvania Surveyors' Conference 2007

Posted by Dave Smith On 1/27/2007 10:20:00 AM 0 comments


I was able to enjoy some time at the Pennsylvania Society of Land Surveyors' 2007 Conference. It was great to see many old friends again, such as the great folks at PSLS that put the conference on, the Penn State Wilkes-Barre Surveying faculty (they have an excellent program there - I was fortunate to be able to tag along as an observer in the last ABET visit to Penn State, and have known Tom Seybert since my own days at Penn State as a student), as well as many fellow surveyors, PAMAGIC members, POBers and other folks - the conversation was great, I got a lot of input and thoughts on Continuing Professional Competency, data standards and geodesy, and many other things swirling around in my life of late.

My focus was to attend some of the GPS sessions, and though I was tied up with many other things, I was actually able to attend some, such as the "Horizontal Control Survey with GPS " session by GPS guru Dr. James P. Reilly, and the "Static GPS Post-Processing" session by Brian Naberezny, of PSU and University of Maine.

I also greatly enjoyed the excellent presentation put on by Patrick Lee, as a Daniel Boone re-enactor. As a pioneer in his westward movements, Daniel Boone was involved in surveying and land grants - and some of my own Searcy ancestors were colleagues of Boone, and were also surveyors in early Kentucky.

Patrick Lee as Daniel Boone



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PSLS Conference

Posted by Dave Smith On 1/22/2007 09:22:00 AM 0 comments


I am looking forward to spending some time over the next few days at the Pennsylvania Surveyors' Conference. It's always a great time to catch up with old friends, as well as get some updates on various things going on in the world of surveying and mapping. This year I am going to focus on the GPS track, something I have not been doing my due dilligence on of late.

On another note, it's beginning to amaze me how many geospatial-related conferences are cropping up of late. I just got a notice of the Rocket City conference in Huntsville, and there have been several others in the last few months and more upcoming. I can certainly understand thematic conferences, regional ones, vendor-
oriented ones... but are we getting to the point where there are just too many?



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"Longitude" - by Dava Sobel

Posted by Dave Smith On 1/15/2007 10:48:00 PM 0 comments

I just finished reading Longitude, by Dava Sobel. An enjoyable read, presented in a great anecdotal style, with plenty of colorful detail and insight into some of the joys and tribulations of John Harrison's attempt to conquer the challenge of accurate determination of longitude. Sobel lays out the background for the challenge, with tragedy at sea and other powerful driving forces, to include a challenge, with a virtual fortune ostensibly to be recieved by the winner...

The dynamic of battles between clockmakers and astronomers, and beyond this, the twists and turns introduced by the both arbitrary and capricious, yet bureaucratic and obstinate Board of Longitude are presented with great wit by Sobel, with our self-taught clockmaker protagonist, John Harrison showing tremendous brilliance and tenacity in the face of adversity after adversity.

A well written, well-researched, and extremely well-presented tale, if with odd continuity from chapter to chapter - I highly recommend it to anyone with an interest in science. Sobel spins an excellent tale, against a richly woven tapestry featuring many other great figures in 18th-century history, such as Astronomers Royal John Flamsteed, Edmond Halley, and Nevil Maskelyne, Captains Cook and Bligh, King George III and many others.

As fast as I read, the stack grows faster... Currently on the stack are re-reading Gödel, Escher, Bach, by Douglas R. Hofstadter, Drawing the Line: Tales of Maps and Cartocontroversy, by Mark Monmonier, I have Tales of the Dervishes by Idries Shah, Metamagical Themas (another Hofstadter book), The Geographer at Work, Mental Maps and a few others from my late Penn State professor Peter Gould and quite a few others working their way to the top of the stack...



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